The present invention relates to a device for connecting a coaxial cable to a printed circuit card.
For connecting coaxial cables to printed circuit cards, devices are known that comprise a tubular socket suitable for being fixed to the card, and a plug suitable for mounting on the end of the coaxial cable and for inserting in the socket.
There exists a need to be able to connect a coaxial cable to a printed circuit card in a direction that is perpendicular to the card.
The invention satisfies this need by means of a connection device for connecting a coaxial cable to a printed circuit card, which device is particularly simple, low cost, and reliable, and comprises:
a tubular socket suitable for fixing to the card; and
a plug suitable for being mounted at the end of a coaxial cable, said plug comprising a tubular plug body and a central contact for connection to the central conductor of the cable,
the socket and the plug being arranged so that the plug can be inserted into the socket in a direction perpendicular to the plane of the printed circuit card, wherein the socket comprises a resilient portion suitable for urging the plug body towards the printed circuit card along said direction so as to hold the central contact of the plug pressed against a conductive track of the printed circuit card.
The resilient force exerted by the resilient portion of the socket serves throughout the life of the connector device to hold the coaxial cable mechanically and reliably to the printed circuit card so as to avoid any interruptions in the electrical connection between the cable and the card.
Preferably, the central contact of the plug has a projection that bears against the conductive track of the printed circuit card, enabling electrical contact to be made directly between the central contact of the plug and the conductive track of the card.
In an embodiment, the resilient portion of the socket is constituted by a plurality of elastically deformable tabs defined by slots formed over at least a fraction of the height of the socket.
Advantageously, the socket has a narrowing in its section in its elastic portion.
The plug body may have a cylindrical central portion extended at each end by a respective tapering portion comprising a top tapering portion having a bearing surface for the elastically deformable tab and a bottom tapering portion whereby the plug is engaged in the socket, the height of the top tapering portion being preferably greater than that of the bottom tapering portion.
Since said bearing surface slopes relative to the axis of the plug body, the tabs, when they press against said surface, exert a force that urges the plug body towards the printed circuit card.
The large bearing surface area provided in this way contributes to providing good mechanical retention of the plug body against the card.
In another embodiment, the resilient portion is constituted by at least one flexible tongue that is folded towards the inside of the socket.
In practice, the central conductor of the cable is mechanically and electrically connected to the central contact of the plug by solder ring or by crimping. According to the invention, the plug body has at least one opening for passing the tools that are necessary for performing the soldering or crimping operations.
Since the outer conductor of the coaxial cable is usually mechanically and electrically connected to the body of the plug by soldering or crimping, the plug body advantageously includes at least one opening for passing the tools that are necessary for performing soldering or crimping operations.
The projection of the central contact of the plug may be rigid.
In the invention, an insulating sleeve is provided that is suitable for being inserted between the projection of the central contact of the plug and the body of the plug.
The insulating sleeve can be elastically deformable, e.g. being made of elastomer, and in particular of silicone.
In a variant, the insulating sleeve is made of polymer foam.
In a particular embodiment, mechanical clearance is provided between the insulating sleeve and the projection of the central contact of the plug, allowing the central contact to move axially.
Advantageously, the device includes an outer bearing piece engaged around the resilient portion of the socket and holding said resilient portion in contact with the plug body.
This bearing piece ensures that the fixing of the plug body in the socket is reliable by preventing the resilient portion thereof from deforming in a direction that would disengage the plug body from the socket.
The bearing piece can be constituted by a cap, in particular a polymer cap.
In a variant, the bearing piece is a resilient ring engaged around the resilient portion of the socket.
The invention also provides a method of connecting a coaxial cable to a printed circuit card in a direction perpendicular to the plane of said card, the method comprising the following steps:
mounting a socket on the printed circuit card, e.g. by soldering, the socket including a resilient portion;
mounting one end of the coaxial cable on a plug comprising a plug body and a central contact, by connecting the central conductor of the cable to said central contact and by connecting the outer conductor of the cable to the plug body e.g. by soldering or by crimping; and
mounting the plug body in the socket in a direction perpendicular to the plane of the printed circuit card, the resilient portion of the socket deforming during said mounting and at the end thereof exerting a force that is directed in a direction substantially perpendicular to the plane of the printed circuit card so as to hold the central contact of the plug against a conductive track of the card.